LOS ANGELES (CNN) -- Michael Jackson's last concert promoter has four hours Wednesday to convince a jury that it is not responsible for the pop icon's death.

AEG Live attorney Marvin Putnam warned in his opening statements in the Jackson wrongful death trial five months ago that he would show "ugly stuff" and reveal Jackson's "deepest, darkest secret."

The revelations that jurors heard from 58 witnesses over 83 days of testimony over 21 weeks included details of Jackson's drug use and his shopping for a doctor to give him the surgical anesthetic propofol that he thought would give him sleep.

Brian Panish, the lead lawyer for Jackson's mother and three children, conceded in his closing Tuesday that the singer may have some fault for his own death, but said "it's about shared responsibility."

Jackson did use prescription painkillers and was warned that using propofol at home to sleep was risky, "but he never had a problem until Dr. Conrad Murray was working and until Conrad Murray negotiated with AEG Live," Panish argued.

He urged jurors to award the family between $1 billion and $2 billion in damages for its share of liability in Jackson's death -- to replace what he would have earned touring, had he lived, and for the personal suffering from the loss of a son and father.

Katherine Jackson testified that she filed the wrongful death lawsuit three years ago against AEG Live "because I want to know what really happened to my son."

Her lawyers argue that the company is liable in the death because it negligently hired, retained or supervised Murray, who was convicted of involuntary manslaughter in Jackson's propofol overdose death.

After AEG Live's Putnam delivers his closing arguments Wednesday, Jackson's lawyer will have another two hours Thursday morning to sum up his arguments in rebuttal.

Twelve jurors, who have sat and listened in a Los Angeles courtroom for 21 weeks, will then begin deliberations.

The judge is allowing a television camera in court for the closing arguments and verdict.

AEG Live's defense

Murray treated Michael Jackson and his children for minor illnesses while they lived in Las Vegas for three years, before the singer returned to Los Angeles to prepare for his "This Is It" comeback tour. It was Jackson -- not AEG Live executives -- who chose Murray to be his full-time doctor for his tour, the company's lawyers contend.

AEG Live Co-CEO Paul Gongaware negotiated to pay Murray $150,000 a month only because of Jackson's request to have his doctor with him as he performed 50 shows at London's O2 Arena, they argue.

There was no need to check Murray's background because he was a licensed, successful doctor who was known to Jackson, they said.

A key argument in the Jackson case is that AEG Live was negligent by not ordering a financial background check of Murray, which would have revealed he was in a dire financial situation and not successful. His desperation to keep his lucrative job led Murray to violate his Hippocratic Oath to do no harm by using the dangerous propofol infusions to put Jackson to sleep each night for two months, Jackson lawyers argue.

AEG Live executives had no way of knowing Murray was treating Jackson's insomnia with propofol in the privacy of his bedroom, their lawyers contend. Jackson was a secretive addict, adept at keeping family, friends and other doctors in the dark about his medical treatments, they argue.

But two doctors testified that they told Gongaware about Jackson's abuse of painkillers and his insomnia during tours in the 1990s, when the AEG Live executive served as tour manager. Jackson lawyers argue Gongaware, who was the top producer on the new tour, should have known that Jackson could suffer the same problems in 2009.

AEG Live can avoid a negative verdict if they are able to convince at least four of the 12 jurors that they did not hire Murray. It is the first of 16 questions on the jury verdict form. If jurors answer it with a "no" -- that AEG Live did not hire the doctor -- they would end their deliberations and the trial.

An AEG Live lawyer e-mailed an employment contract to Murray on the morning of June 24, 2009. Murray signed it and faxed it back to the company that day. But the signature line for AEG Live's CEO and Michael Jackson were never signed since Jackson died the next day.

Putnam will point to those blank signature lines as evidence that Murray was never hired by his client. There were negotiations with Murray, but he was never paid, the AEG Live lawyer argues.

Panish, the lead Jackson lawyer, told jurors Tuesday that all the elements of an oral contract -- "just as valid as a written contract" -- were in place when Jackson died.

Murray had been treating Jackson for two month and the written contract stated that his start day was May 1, 2009. A series of e-mail exchanges involving Murray and AEG Live executives and lawyers supported his argument, Panish said.

Blame and damages

If the jury concludes AEG Live has liability, it would have to decide how much the company should pay in economic and personal damages to Jackson's mother and children. They can use estimates of Jackson's "lost earnings capacity" -- the amount of money he could reasonably be expected to have earned if he had lived -- to guide them.

AEG Live expert Eric Briggs testified it was "speculative" that Jackson would have even completed another tour because of his drug use, damaged reputation and history of failed projects. He suggested the star may never have earned another dime.

Putnam's closing argument about damages must overcome the impression left on jurors Tuesday when Panish played a video montage of Jackson performances.

"That is, I think, the best evidence of if Michael Jackson could have sold tickets -- not what Mr. Briggs would tell you," Panish told jurors.

Panish suggested jurors pick a number between $900 million and $1.6 billion for economic damages. They should add on another $290 million for non-economic damages -- or personal damages, he said.

The last question on the verdict form asks jurors to assign a percentage that they believe represents Michael Jackson's share of blame in his death. The total damages owed by AEG Live would be reduced by that percentage.

Marvin Putnam, when he concludes Wednesday, could be expected to argue Michael Jackson is 100% to blame.

Panish will have another two hours to rebut Putnam's arguments before jury deliberations begin Thursday.